Thin-film magnetic head structure adapted to manufacture a thin-film head having a base magnetic pole part, a yoke magnetic pole part, and an intervening insulative film

ABSTRACT

A thin-film magnetic head structure has a configuration adapted to manufacture a thin-film magnetic head configured such that a main magnetic pole layer including a magnetic pole end part on a side of a medium-opposing surface opposing a recording medium, a write shield layer opposing the magnetic pole end part so as to form a recording gap layer on the medium-opposing surface side, and a thin-film coil wound about the write shield layer or main magnetic pole layer are laminated. The main magnetic pole layer includes a base magnetic pole part comprising the magnetic pole end part and a base depression distanced farther from the medium-opposing surface than the magnetic pole end part, and an embedded magnetic pole part buried in the base depression and joined to the base magnetic pole part. The thin-film magnetic head structure includes a yoke magnetic pole part joined to the base magnetic pole part and embedded magnetic pole part at a position distanced farther from the medium-opposing surface than the recording gap layer, and an intervening insulative film disposed between the embedded magnetic pole part and yoke magnetic pole part at a position distanced farther from the medium-opposing surface than the recording gap layer.

TECHNICAL FIELD

The present invention relates to a thin-film magnetic head structure formanufacturing a thin-film magnetic head which performs magneticrecording operations by perpendicular recording, a method ofmanufacturing the same, and a thin-film magnetic head.

BACKGROUND OF THE INVENTION

In recent years, the areal density in hard disk drives has beenincreasing remarkably. Recently, the areal density in hard disk driveshas reached 160 to 200 GB/platter in particular, and is about toincrease further. Accordingly, thin-film magnetic heads have beenrequired to improve their performances.

In terms of recording schemes, thin-film magnetic heads can roughly bedivided into those for longitudinal recording in which information isrecorded in a (longitudinal) direction of a recording surface of a harddisk (recording medium) and those for perpendicular recording in whichdata is recorded while the direction of recording magnetization formedin the hard disk is perpendicular to the recording surface. As comparedwith the thin-film magnetic heads for longitudinal recording, thethin-film magnetic heads for perpendicular recording have beenconsidered more hopeful, since they can realize a much higher recordingdensity while their recorded hard disks are less susceptible to thermalfluctuations.

Conventional thin-film magnetic heads for perpendicular recording aredisclosed, for example, in U.S. Pat. No. 6,504,675, U.S. Pat. No.4,656,546, U.S. Pat. No. 4,672,493, and Japanese Patent ApplicationLaid-Open No. 2004-94997.

Meanwhile, when thin-film magnetic heads for perpendicular recordingrecord data onto areas in inner and outer peripheries of a hard disk, amagnetic pole end part disposed on the side of a medium-opposing surface(also referred to as air bearing surface, ABS) opposing the recordingmedium (hard disk) yields a certain skew angle with respect to a datarecording track. In perpendicular magnetic recording heads (hereinafteralso referred to as “PMR”) having a high writing capability, the skewangle has caused a problem of so-called side fringe in which unnecessarydata are recorded between adjacent tracks. The side fringe adverselyaffects the detection of servo signals and the S/N ratio of reproducedwaveforms. Therefore, in conventional PMRs, the magnetic pole end parton the ABS side in the main magnetic pole layer has a bevel formgradually narrowing in width toward one direction (see, for example,Japanese Patent Application Laid-Open Nos. 2003-242067 and 2003-203311in this regard).

OBJECT AND SUMMARY OF THE INVENTION

However, the conventional PMRs have been problematic in that they causea phenomenon known as pole erasure by which data recorded beforehand ona hard disk is erased when information is further recorded at a highdensity. The pole erasure is a phenomenon in which, after data iswritten on a recording medium (hard disk) having a high maximumcoercivity Hc, a leakage magnetic flux flows from the ABS to the harddisk even when no write current flows through a thin-film coil, therebyerasing the other data.

This point will be explained in further detail.

An example of the conventional PMRs is a thin-film magnetic head 400having a structure shown in FIGS. 29(A), (B), and (C). This thin-filmmagnetic head 400 includes a main magnetic pole layer 402 which isformed on an insulating layer 401 and has a bevel-shaped magnetic poleend part disposed on the side of an ABS 403; a write shield layer 405which is magnetically connected to the main magnetic pole layer 402 andopposes the main magnetic pole layer 402 by way of a recording gap layer404 on the ABS 403 side; and a thin-film coil 406. The thin-film coil406 is wound in a planar spiral about a junction 408 connecting the mainmagnetic pole layer 402 and the write shield layer 405, while itswindings are insulated from each other by a photoresist 407.

In the conventional PMRs, as in the thin-film magnetic head 400, amagnetic material is magnetized such that the direction of magnetizationms is oriented so as to extend along the ABS 403, whereby the mainmagnetic pole layer 402 is formed.

In the conventional PMRs such as the thin-film magnetic head 400,however, even when the direction of magnetization ms is oriented so asto extend along the ABS 403, the direction of remnant magnetization mrinside the main magnetic pole layer 402 after completion of writing isoriented toward the ABS 403 side and thus faces a different directionthan the magnetization ms. (The direction different from that extendingalong the ABS will be referred to as “different direction” in thefollowing.) Therefore, when such a PMR writes data, leakage magneticfluxes due to the remnant magnetization mr may erase data alreadywritten on a hard disk or weaken signals of written data even though nowrite current is flowing.

In order to overcome the problem mentioned above, it is an object of thepresent invention to provide a thin-film magnetic head structure whichcan manufacture a thin-film magnetic head comprising a structure capableof preventing the pole erasure from occurring while improving therecording density, a method of manufacturing the same, and a thin-filmmagnetic head.

For solving the above-mentioned problem, in one aspect, the presentinvention provides a thin-film magnetic head structure adapted tomanufacture a thin-film magnetic head configured such that a mainmagnetic pole layer including a magnetic pole end part on a side of amedium-opposing surface opposing a recording medium, a write shieldlayer opposing the magnetic pole end part so as to form a recording gaplayer on the medium-opposing surface side, and a thin-film coil woundabout the write shield layer or main magnetic pole layer are laminated;wherein the main magnetic pole layer includes a base magnetic pole partcomprising the magnetic pole end part and a base depression distancedfarther from the medium-opposing surface than the magnetic pole endpart, and an embedded magnetic pole part buried in the base depressionand joined to the base magnetic pole part; and wherein the thin-filmmagnetic head structure includes a yoke magnetic pole part joined to thebase magnetic pole part and embedded magnetic pole part at a positiondistanced farther from the medium-opposing surface than the recordinggap layer, and an intervening insulative film disposed between theembedded magnetic pole part and yoke magnetic pole part at a positiondistanced farther from the medium-opposing surface than the recordinggap layer.

In this thin-film magnetic head structure, the joint between the basemagnetic pole part having the magnetic pole end part and the embeddedmagnetic pole part blocks the emission of remnant magnetization from theembedded magnetic pole part to the magnetic pole end part. Since theembedded magnetic pole part and the yoke magnetic pole part are joinedto each other by way of the intervening insulative film, the quantity ofmagnetism increases, so as to improve the overwrite characteristic,whereas the intervening insulative film can block the emission ofremnant magnetization from the yoke magnetic pole part.

The thin-film magnetic head structure may further comprise a baseinsulating layer including a magnetic pole forming depression sunkeninto a form corresponding to the main magnetic pole layer, the magneticpole forming depression having a very narrow groove part formed so as todefine a track width of the thin-film magnetic head, whereas the basemagnetic pole part is arranged at the magnetic pole forming depressionin the base insulating layer.

In this case, the main magnetic pole layer is formed so as to beembedded in the magnetic pole forming depression.

In the thin-film magnetic head structure, the base magnetic pole partand the embedded magnetic pole part may be joined to each other at afirst contact area disposed between the medium-opposing surface and thethin-film coil, and at a second contact area disposed at a positiondistanced farther from the medium-opposing surface than the thin-filmcoil.

In this case, the base magnetic pole part and the embedded magnetic poleare joined to each other in the vicinity of the medium-opposing surface.

In the thin-film magnetic head structure, the saturated magnetic fluxdensity of the base magnetic pole part may be set higher than thesaturated magnetic flux density of the embedded magnetic pole part.

This can prevent the overwrite characteristic from deteriorating alongwith the saturation with the magnetic flux.

In another aspect, the present invention provides a thin-film magnetichead structure adapted to manufacture a thin-film magnetic headconfigured such that a main magnetic pole layer including a magneticpole end part on a side of a medium-opposing surface opposing arecording medium, a write shield layer opposing the magnetic pole endpart so as to form a recording gap layer on the medium-opposing surfaceside, and a thin-film coil wound about the write shield layer or mainmagnetic pole layer are laminated; wherein the main magnetic pole layerincludes a base magnetic pole part comprising the magnetic pole end partand a base depression distanced farther from the medium-opposing surfacethan the magnetic pole end part, an embedded magnetic pole part buriedin the base depression and joined to the base magnetic pole part, and astepped part with a variable thickness at a position distanced fartherfrom the medium-opposing surface than the recording gap layer, thethickness at a position distanced farther from the medium-opposingsurface than the stepped part being formed greater than the thickness ata position closer to the medium-opposing surface than the stepped part;and wherein the thin-film magnetic head structure includes a yokemagnetic pole part joined to the base magnetic pole part and embeddedmagnetic pole part at a position distanced farther from themedium-opposing surface than the recording gap layer.

As the thickness is greater at a position distanced farther from themedium-opposing surface than the stepped part, this thin-film magnetichead structure increases the quantity of magnetism and improves theoverwrite characteristic.

The thin-film magnetic head structure may further comprise a baseinsulating layer including a magnetic pole forming depression sunkeninto a form corresponding to the main magnetic pole layer, the magneticpole forming depression having a very narrow groove part formed so as todefine a track width of the thin-film magnetic head, whereas the basemagnetic pole part is arranged at the magnetic pole forming depressionin the base insulating layer.

In this case, the main magnetic pole layer is formed so as to beembedded in the magnetic pole forming depression.

The main magnetic pole layer in the thin-film magnetic head structuremay have an expanded area with a width expanded along themedium-opposing surface.

As the expanded area having the width expanded along the medium-opposingsurface is provided, the quantity of magnetism increases, therebyimproving the overwrite characteristic.

The magnetic pole forming depression in the thin-film magnetic headstructure may have a variable depth structure whose depth changes at astepped line disposed at a position distanced farther from themedium-opposing surface than the recording gap layer.

This forms areas with different thicknesses in the main magnetic polelayer formed as being embedded in the magnetic pole forming depression.

In still another aspect, the present invention provides a method ofmanufacturing a thin-film magnetic head structure adapted to manufacturea thin-film magnetic head configured such that a main magnetic polelayer including a magnetic pole end part on a side of a medium-opposingsurface opposing a recording medium, a write shield layer opposing themagnetic pole end part so as to form a recording gap layer on themedium-opposing surface side, and a thin-film coil wound about the writeshield layer or main magnetic pole layer are laminated; the methodcomprising the steps of:

(1) forming a base insulating layer including a magnetic pole formingdepression sunken into a form corresponding to the main magnetic polelayer, the magnetic pole forming depression having a very narrow groovepart formed so as to define a track width of the thin-film magnetichead;

(2) forming a film-like magnetic pole part at an inner periphery in anarea other than the very narrow groove part in the magnetic pole formingdepression by a first magnetic material while embedding the firstmagnetic material into the very narrow groove part formed in the baseinsulating layer;

(3) embedding a second magnetic material different from the firstmagnetic material into the inside of the film-like magnetic pole part;

(4) surface-flattening the first magnetic material and second magneticmaterial on a side closer to the thin-film coil, so as to cause thefirst magnetic material embedded in the very narrow groove part to formthe magnetic pole end part, and cause a base magnetic pole partconstituted by the magnetic pole end part and film-like magnetic polepart and the second magnetic material embedded in the inside of thefilm-like magnetic pole part to form the main magnetic pole layer havingan embedded junction structure;

(5) forming the surface-flattened base magnetic pole part and embeddedmagnetic pole part with the recording gap layer and an interveninginsulative film disposed at a position distanced farther from themedium-opposing surface than the recording gap layer;

(6) forming a yoke magnetic pole part joined to the base magnetic polepart and embedded magnetic pole part at a part where no interveninginsulative film exists;

(7) forming the thin-film coil such that the thin-film coil comes intocontact with the yoke magnetic pole part by way of an insulating film;and

(8) forming the write shield layer such that the write shield layerfaces the magnetic pole end part by way of the recording gap layer.

In this manufacturing method, a magnetic material having a saturatedmagnetic flux density lower than that of the first magnetic material maybe used as the second magnetic material.

In still another aspect, the present invention provides a method ofmanufacturing a thin-film magnetic head structure adapted to manufacturea thin-film magnetic head configured such that a main magnetic polelayer including a magnetic pole end part on a side of a medium-opposingsurface opposing a recording medium, a write shield layer opposing themagnetic pole end part so as to form a recording gap layer on themedium-opposing surface side, and a thin-film coil wound about the writeshield layer or main magnetic pole layer are laminated; the methodcomprising the steps of:

(1) forming a base insulating layer including a magnetic pole formingdepression sunken into a form corresponding to the main magnetic polelayer, the magnetic pole forming depression having a very narrow groovepart formed so as to define a track width of the thin-film magnetic headand sunken into a form corresponding to the main magnetic pole layerwith a depth changing at a stepped line disposed at a position distancedfarther from the medium-opposing surface than the recording gap layer soas to become greater on the side distanced farther from themedium-opposing surface than the stepped line;

(2) forming a film-like magnetic pole part at an inner periphery in anarea other than the very narrow groove part in the magnetic pole formingdepression by a first magnetic material while embedding the firstmagnetic material into the very narrow groove part formed in the baseinsulating layer;

(3) embedding a second magnetic material different from the firstmagnetic material into the inside of the film-like magnetic pole part;

(4) surface-flattening the first magnetic material and second magneticmaterial on a side closer to the thin-film coil, so as to cause thefirst magnetic material embedded in the very narrow groove part to formthe magnetic pole end part, and cause a base magnetic pole partconstituted by the magnetic pole end part and film-like magnetic polepart and the second magnetic material embedded in the inside of thefilm-like magnetic pole part to form the main magnetic pole layer havingan embedded junction structure;

(5) forming the surface-flattened base magnetic pole part and embeddedmagnetic pole part with the recording gap layer;

(6) forming a yoke magnetic pole part joined to the base magnetic polepart and embedded magnetic pole part;

(7) forming the thin-film coil such that the thin-film coil comes intocontact with the yoke magnetic pole part by way of an insulating film;and

(8) forming the write shield layer such that the write shield layerfaces the magnetic pole end part by way of the recording gap layer.

The manufacturing method may further comprise the step of expanding awidth of the magnetic pole forming depression along the stepped line.

In still another aspect, the present invention provides a thin-filmmagnetic head configured such that a main magnetic pole layer includinga magnetic pole end part on a side of a medium-opposing surface opposinga recording medium, a write shield layer opposing the magnetic pole endpart so as to form a recording gap layer on the medium-opposing surfaceside, and a thin-film coil wound about the write shield layer or mainmagnetic pole layer are laminated; wherein the main magnetic pole layerincludes a base magnetic pole part comprising the magnetic pole end partand a base depression distanced farther from the medium-opposing surfacethan the magnetic pole end part, and an embedded magnetic pole partburied in the base depression and joined to the base magnetic pole part;and wherein the thin-film magnetic head includes a yoke magnetic polepart joined to the base magnetic pole part and embedded magnetic polepart at a position distanced farther from the medium-opposing surfacethan the recording gap layer, and an intervening insulative filmdisposed between the embedded magnetic pole part and yoke magnetic polepart at a position distanced farther from the medium-opposing surfacethan the recording gap layer.

In still another aspect, the present invention provides a thin-filmmagnetic head configured such that a main magnetic pole layer includinga magnetic pole end part on a side of a medium-opposing surface opposinga recording medium, a write shield layer opposing the magnetic pole endpart so as to form a recording gap layer on the medium-opposing surfaceside, and a thin-film coil wound about the write shield layer or mainmagnetic pole layer are laminated; wherein the main magnetic pole layerincludes a base magnetic pole part comprising the magnetic pole end partand a base depression distanced farther from the medium-opposing surfacethan the magnetic pole end part, an embedded magnetic pole part buriedin the base depression and joined to the base magnetic pole part, and astepped part with a variable thickness at a position distanced fartherfrom the medium-opposing surface than the recording gap layer, thethickness at a position distanced farther from the medium-opposingsurface than the stepped part being formed greater than the thickness ata position closer to the medium-opposing surface than the stepped part;and wherein the thin-film magnetic head includes a yoke magnetic polepart joined to the base magnetic pole part and embedded magnetic polepart at a position distanced farther from the medium-opposing surfacethan the recording gap layer.

The present invention will be more fully understood from the detaileddescription given hereinbelow and the accompanying drawings which aregiven by way of illustration only, and thus are not to be considered aslimiting the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of the thin-film magnetic head structurerelated to the present invention, in which (A) is a sectional view takenalong a direction intersecting a thin-film coil, and (B) is a sectionalview showing the ABS when cut at the ABS;

FIG. 2 is a plan view of the thin-film magnetic head structure shown inFIG. 1 as focused on its main magnetic pole layer;

FIG. 3 is a view showing an insulating layer, in which (A) is a planview, and (B) is a sectional view taken along the line B-B of (A);

FIG. 4 is a view showing a major part of FIG. 3 under magnification withchanged ratios of dimensions, in which (A) is a plan view, and (B) is asectional view taken along the line B-B of (A);

FIG. 5 is a view showing the main magnetic pole layer and upper yokemagnetic pole part after being cut along the ABS, in which (A) is aperspective view, and (B) is a sectional view taken along the line B-Bof (A);

FIG. 6 is a sectional view of the thin-film magnetic head structure inaccordance with a first embodiment of the present invention, in which(A) is a sectional view taken along a direction intersecting thethin-film coil, and (B) is a sectional view showing the ABS when cut atthe ABS;

FIG. 7 is a plan view of the thin-film magnetic head structure inaccordance with the first embodiment as focused on the main magneticpole layer;

FIG. 8 is a plan view showing the main magnetic pole layer;

FIG. 9 is a sectional view showing the ABS in a first modified exampleof the thin-film magnetic head structure in accordance with the presentinvention when cut at the ABS;

FIG. 10 is a sectional view showing the ABS in a second modified exampleof the thin-film magnetic head structure in accordance with the presentinvention when cut at the ABS;

FIG. 11 is a plan view or sectional view in a step of the manufacturingmethod in accordance with the first embodiment, in which (A) is a planview, (B) is a sectional view taken along the line B-B of (A), (C) is aplan view showing a major part of (A) under magnification with changedratios of dimensions, and (D) is a sectional view taken at the ABS 30 in(B);

FIG. 12 is a plan view or sectional view in a step subsequent to FIG.11, in which (A) is a plan view, (B) is a sectional view taken along theline B-B of (A), (C) is a plan view showing a major part of (A) undermagnification with changed ratios of dimensions, and (D) is a sectionalview taken at the ABS 30 in (B);

FIG. 13 is a plan view or sectional view in a step subsequent to FIG.12, in which (A) is a plan view, (B) is a sectional view taken along theline B-B of (A), (C) is a plan view showing a major part of (A) undermagnification with changed ratios of dimensions, and (D) is a sectionalview taken at the ABS 30 in (B);

FIG. 14 is a plan or sectional view in a step subsequent to FIG. 13, inwhich (A) is a plan view, (B) is a sectional view taken along the lineB-B of (A), (C) is a plan view showing a major part of (A) undermagnification with changed ratios of dimensions, and (D) is a sectionalview taken at the ABS 30 in (B);

FIG. 15 is a plan view or sectional view in a step subsequent to FIG.14, in which (A) is a plan view showing an intervening insulative filmand its surroundings, (B) is a sectional view taken along the line B-Bof (A), and (C) is a sectional view taken at the ABS 30 in (B);

FIG. 16 is a sectional view in a step subsequent to FIG. 15, in which(A) is a sectional view corresponding to the line B-B in FIGS. 15(A),and (B) is a sectional view cut at the ABS in (A);

FIG. 17 is a sectional view of the thin-film magnetic head structure inaccordance with a second embodiment of the present invention, in which(A) is a sectional view taken along a direction intersecting thethin-film coil, and (B) is a sectional view showing the ABS when cut atthe ABS;

FIG. 18 is a view showing an insulating layer, in which (A) is a planview, (B) is a sectional view taken along the line B-B in (A), and (C)is a sectional view taken along the line C-C in (A);

FIG. 19 is a view showing the main magnetic pole layer and upper yokemagnetic pole part after being cut along the ABS, in which (A) is aperspective view, and (B) is a sectional view taken along the line B-Bof (A);

FIG. 20 is a plan view or sectional view in a step of the manufacturingmethod in accordance with the second embodiment, in which (A) is a planview, (B) is a sectional view taken along the line B-B of (A), (C) is aplan view showing a major part of (A) under magnification with changedratios of dimensions, and (D) is a sectional view taken at the ABS 30 in(B);

FIG. 21 is a plan view or sectional view in a step subsequent to FIG.20, in which (A) is a plan view, (B) is a sectional view taken along theline B-B of (A), (C) is a plan view showing a major part of (A) undermagnification with changed ratios of dimensions, and (D) is a sectionalview taken at the ABS 30 in (B);

FIG. 22 is a plan view or sectional view in a step subsequent to FIG.21, in which (A) is a plan view, (B) is a sectional view taken along theline B-B of (A), (C) is a plan view showing a major part of (A) undermagnification with changed ratios of dimensions, and (D) is a sectionalview taken at the ABS 30 in (B);

FIG. 23 is a sectional view in a step subsequent to FIG. 22, in which(A) is a sectional view corresponding to the line B-B in FIGS. 22(A),and (B) is a sectional view cut at the ABS in (A);

FIG. 24 is a plan view or sectional view in a step subsequent to FIG.23, in which (A) is a plan view, (B) is a sectional view taken along theline B-B of (A), (C) is a plan view showing a major part of (A) undermagnification with changed ratios of dimensions, and (D) is a sectionalview taken at the ABS 30 in (B);

FIG. 25 is a sectional view showing a conventional method ofmanufacturing a thin-film magnetic head, in which (A) and (B) illustraterespective states before and after etching;

FIG. 26 is a plan view showing the main magnetic pole layer in aconventional thin-film magnetic head, in which (A) illustrates the mainmagnetic pole layer as set, and (B) illustrates the main magnetic polelayer manufactured;

FIG. 27 is a sectional view showing a conventional method ofmanufacturing a thin-film magnetic head, in which (A) illustrates astate provided with a photoresist, and (B) illustrates a state afterremoving the photoresist;

FIG. 28 is a sectional view showing a conventional method ofmanufacturing a thin-film magnetic head, in which (A) illustrates astate provided with another photoresist, and (B) illustrates a stateafter removing the photoresist; and

FIG. 29 shows an example of conventional thin-film magnetic heads, inwhich (A) is a sectional view, (B) is a front view showing the ABS, and(C) is a plan view.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following, embodiments of the present invention will be explainedwith reference to the drawings. Constituents identical to each otherwill be referred to with numerals identical to each other withoutrepeating their overlapping descriptions.

First Embodiment

Configuration of Thin-Film Magnetic Head Structure

The thin-film magnetic head structure in accordance with the presentinvention will be explained first with reference to FIGS. 1 to 8, andthen the thin-film magnetic head structure in accordance with the firstembodiment of the present invention will be explained. FIG. 1 is asectional view of a thin-film magnetic head structure 300 related to thepresent invention, in which (A) is a sectional view taken along adirection intersecting a thin-film coil, and (B) is a sectional viewshowing the ABS when cut at the ABS. FIG. 2 is a plan view of thethin-film magnetic head structure 300 as focused on its main magneticpole layer 10.

The thin-film magnetic head structure 300 has a configuration adapted tomanufacture a magnetic head for perpendicular recording. The thin-filmmagnetic head structure 300 is formed on a substrate which is notdepicted, and yields a thin-film magnetic head in the present inventionwhen cut at an ABS 30 which is a medium-opposing surface opposing arecording medium (hard disk).

The thin-film magnetic head structure 300 comprises a substrate; areproducing head structure, laminated on the substrate, formanufacturing a reproducing head comprising an MR device(magnetoresistive device) or the like; and a recording head structurefor manufacturing a recording head. FIGS. 1(A) and (B) show therecording head structure laminated on the insulating layer 1, whileomitting the substrate and the reproducing head structure.

The configuration of a major part of the recording head structure in thethin-film magnetic head structure 300 will be explained in thefollowing, whereas the configuration of the other parts will beexplained in manufacturing steps which will be set forth later. Eachconstituent in the recording head structure will be explained with thesame name and numeral before and after being cut at the ABS 30 unlessotherwise specified. When distinguishing these states from each other,however, “′” will be added to the numeral referring to the state afterbeing cut at the ABS 30.

The thin-film magnetic head structure 300 comprises the insulating layer1, and a main magnetic pole layer 10, a recording gap layer 24, a writeshield layer 40, and a thin-film coil 100 which are laminated on theinsulating layer 1.

The insulating layer 1 is the base insulating layer in the presentinvention and is formed in a predetermined region on the substrate. FIG.3 is a view showing the insulating layer 1, in which (A) is a plan view,and (B) is a sectional view taken along the line B-B of (A). FIG. 4 is aview showing a major part of FIG. 3 under magnification, in which (A) isa plan view, and (B) is a sectional view taken along the line B-B of(A). In the insulating layer 1, FIG. 3 shows a rectangular predeterminedregion focused on a cavity 2 which will be explained later.

The insulating layer 1 is made of alumina (Al₂O₃) and has the cavity 2at a center part (hatched part in FIGS. 3(A) and 4(A)) on the side of asurface to be formed with a recording head. The cavity 2 is the magneticpole forming depression in the present invention, and is sunken into aform corresponding to the outer shape of the main magnetic pole layer 10in order to form the main magnetic pole layer 10 in set dimensions andshape. Namely, as will be explained later in detail, the cavity 2 isformed earlier than the main magnetic pole layer 10, such that itsdimensions and shape including the depth d1 (about 0.25 to 0.35 μm,preferably 0.3 μm), width, and length coincide with assumed thickness,width, and length of the main magnetic pole layer 10. The cavity 2includes a very narrow groove part 3, a variable width depression 4, afixed width depression 5, and a protruded depression 6, whereas amagnetic material embedded therein forms the main magnetic pole layer10.

The very narrow groove part 3 is formed so as to define the track widthof the thin-film magnetic head, and has a structure adapted to improvethe recording density by reducing the track width. As shown in FIG. 4,the length of the very narrow groove part 3 is set to L1 (longer than aneck height NH which will be explained later, i.e., L1>NH) such that theABS 30 can be secured in an intermediate part of the length. The groovewidth intersecting the length on the surface side is W3, and is W4 onthe lower side, whereas the groove widths W3 and W4 are made narrowerthan the variable width depression 4 and fixed width depression 5 asmuch as possible, so as to yield a very narrow structure in order toimprove the recording density of the thin-film magnetic head. Also, thegroove width gradually decreases along the depth such that a magneticpole end part 11 a, which will be explained later, in the main magneticpole layer 10 has a bevel form. Namely, the groove width W4 is smallerthan the groove width W3 (W3>W4) in the very narrow groove part 3, sothat the bevel angle θ shown in (B) of FIG. 4 becomes about 7 to 12degrees (e.g., 10 degrees).

The variable width depression 4, whose groove width gradually increases,is connected to an end part on the deeper side (one side) of the verynarrow groove part 3. The fixed width depression 5 having a constantgroove width is connected to the variable width depression 4. Thevariable width depression 4 and fixed width depression 5 in total arewider than the very narrow groove part 3. The distance from the boundarypart between the variable width depression 4 and very narrow groove part3 to the ABS 30 will later become the neck height NH. The protrudeddepression 6 is connected to the end part of the very narrow groove part3 opposite from the variable width depression 4.

As shown in FIG. 5, the main magnetic pole layer 10′ (as with the mainmagnetic pole layer 10 before cutting) comprises a base magnetic polepart 11′ and an embedded magnetic pole part 20′, while furthercomprising an upper yoke magnetic pole part 45′ joined thereto. FIG. 5is a view showing the main magnetic pole layer 10′ and upper yokemagnetic pole part 45′ after being cut along the ABS 30, in which (A) isa perspective view, and (B) is a sectional view taken along the line B-Bof (A). For convenience of illustration, FIG. 5 shows the upper yokemagnetic pole part 45′ by dash-double-dot lines. The main magnetic polelayer 10′ is formed so as to be embedded in the cavity 2.

The base magnetic pole part 11′ (as with the base magnetic pole part 11before cutting) comprises a magnetic pole end part 11 a having a verynarrow width corresponding to the very narrow groove part 3, and a yokepart 11 b corresponding to the variable width depression 4 and fixedwidth depression 5. In order to achieve a higher data recording densityby the thin-film magnetic head, the magnetic pole end part 11 a has anarrow track width structure in which a width W1 to be explained lateris narrowed. However, the base magnetic pole part 11′ uses a magneticmaterial (Hi-Bs material) having a saturated magnetic flux densityhigher than that of the embedded magnetic pole part 20′ so that themagnetic pole end part 11 a is not saturated with magnetic fluxes evenin the narrow track width structure. The base magnetic pole part 11′ andembedded magnetic pole part 20′ are magnetized such that the directionof magnetization ms aligns with the ABS 30 (see FIG. 8).

The magnetic pole end part 11 a has a fixed width for defining the trackwidth, which is determined by the very narrow groove part 3. As shown inFIG. 1(B), along the ABS 30, the magnetic pole end part 11 a has a widthW1 on the side closer to the thin-film coil 100, and a width W2 on theside distanced farther from the thin-film coil 100, thereby yielding abevel form whose width gradually decreases in the direction away fromthe thin-film coil 100 (W1>W2, whereas the width W1 is the track width).These widths W1 and W2 correspond to the groove widths W3 and W4 of thevery narrow groove part 3 in the cavity 2, respectively.

The length of the magnetic pole end part 11 a (distance from the ABS 30)corresponds to the neck height NH (which is on the order of 0.1 to 0.3μm, preferably 0.15 μm in this embodiment).

Leaving a peripheral area 11 c corresponding to the variable widthdepression 4 and fixed width depression 5, the inside of the yoke part11 b is a base depression 11 d, in which the embedded magnetic pole part20 is buried. The yoke part 11 b is joined to all the side and bottomfaces of the embedded magnetic pole part 20′ excluding the upper face.As a consequence, the main magnetic pole layer 10′ has an embeddedjunction structure in which the yoke part 11 b excluding the magneticpole end part 11 a of the base magnetic pole part 11′ and the embeddedmagnetic pole part 20′ buried in the base depression 11 d are joinedtogether. If the same magnetic material as with the base magnetic polepart 11′ is used here as a magnetic material constituting the embeddedmagnetic pole part 20′, the pole erasure will be likely to occur.Therefore, the embedded magnetic pole part 20′ employs a magneticmaterial (soft material) having a saturated magnetic flux density lowerthan that of the magnetic material (Hi-Bs material) for the basemagnetic pole part 11′.

The upper yoke magnetic pole part 45′ uses a magnetic material (Hi-Bsmaterial) having a saturated magnetic flux density higher than that ofthe embedded magnetic pole part 20′. At a position distanced fartherfrom the ABS 30 than the recording gap layer 24, the upper yoke magneticpole part 45′ is joined to the surface of the yoke part 11 b of the basemagnetic pole part 11′ and embedded magnetic pole part 20 partlyexcluding on the ABS 30 side. The upper yoke magnetic pole part 45′corresponds to the yoke magnetic pole part in the present invention.

Referring to FIGS. 1 and 2 again, the recording gap layer 24 is formedbetween the magnetic pole end part 11 a, embedded magnetic pole part 20and a first shield layer 41 to be explained later in the write shieldlayer 40 and the insulating part 51. The insulating part 51 is formed byan insulating material buried between the write shield layer 40 andupper yoke magnetic pole part 45 such that no keyholes occur. Further,by way of an insulating film 31 connected to the insulating part 51, thethin-film coil 100 is formed on the surface side of the upper yokemagnetic pole part 45. The surface of the write shield layer 40 iscovered with an overcoat layer 37 made of alumina (Al₂O₃).

The write shield layer 40 comprises the first shield part 41, a secondshield part 42, and a third shield part 43. The first shield part 41 isformed so as to oppose the magnetic pole end part 11 a of the basemagnetic pole part 11 by way of the recording gap layer 24 on the ABS 30side, whereby the neck height NH is determined by the distance from theABS 30 in a direction intersecting the ABS 30.

The second shield part 42 is formed so as to magnetically connect withthe first shield part 41 and upper yoke magnetic pole part 45, and has aheight equivalent to the thickness of the thin-film coil 100.

The third shield part 43 is formed so as to connect with the secondshield part 42 and cover the thin-film coil 100 and a photoresist 101 byway of an insulating layer 32.

The thin-film coil 100 is wound in a planar spiral about the writeshield layer 40 while being insulated therefrom by way of the insulatinglayers 31, 32. Though not depicted, the thin-film magnetic head 100 maybe changed to a helical coil spirally wound about the main magnetic polelayer 10.

Between the main magnetic pole layer 10 and the insulating layer 1, analumina (Al₂O₃) film 16 a aimed at adjusting the track width, anonmagnetic film 16 b made of Ta or Ru, and a magnetic film 16 c made ofCoFeN (24 kG) or CoNiFe (10 kG) are formed successively from theinsulating layer 1 side. It is desirable for the nonmagnetic film 16 bto have a lower resistance so as to become a seed electrode forembedding a magnetic material in the cavity 2 by plating. The magneticfilm 16 c may be omitted when the nonmagnetic film 16 b is formed.

In connection with thus configured thin-film magnetic head structure 300having the foregoing structure, the thin-film magnetic head structure301 in accordance with the first embodiment of the present inventionwill be explained. FIG. 6 is a sectional view of the thin-film magnetichead structure in accordance with the first embodiment of the presentinvention, in which (A) is a sectional view taken along a directionintersecting the thin-film coil, and (B) is a sectional view showing theABS when cut at the ABS. FIG. 7 is a plan view of the thin-film magnetichead structure focused on its main magnetic pole layer. FIG. 8 is a planview of the main magnetic pole layer 10′. Since the thin-film magnetichead structure 301 has a structure in common with the above-mentionedthin-film magnetic head structure 300, the following explanation will befocused on features different from each other while omitting orsimplifying their common features.

The thin-film magnetic head structure 301 includes an interveninginsulative film 22 which is made of the same material as that of therecording gap layer 24 and disposed between the embedded magnetic polepart 20 and the upper yoke magnetic pole part 45 at a position distancedfarther from the ABS 30 than the recording gap layer 24. At portionswhere the intervening insulative film 22 does not exist, the upper yokemagnetic pole part 45 is joined to the embedded magnetic pole part 20.Namely, as shown in FIG. 6, the upper yoke magnetic pole part 45 isjoined to the embedded magnetic pole part 20 at a first contact area 45a disposed between the thin-film coil 100 and ABS 30 and at a secondcontact area 45 b at a position distanced farther from the ABS 30 thanthe thin-film coil 100.

When the thin-film magnetic head structures 300, 301 having theforegoing configuration are cut at an intermediate part of the verynarrow groove part 3 so as to form the ABS 30, the thin-film magneticheads 300A (see FIG. 1) and 301A (see FIG. 6) are obtained.

In conventional PMRs, as in the above-mentioned thin-film magnetic head400 shown in FIG. 29, the main magnetic pole layer 402 is formed by thesame magnetic material from the ABS 403 to the opposite end part by wayof the thin-film coil. Therefore, the remnant magnetization mr isdirected to the ABS 403, thus making it difficult to prevent the poleerasure from occurring.

In the above-mentioned thin-film magnetic heads 300, 301, however, therecording head structure includes the above-mentioned main magnetic polelayer 10, whereas the main magnetic pole layer 10 has an embeddedjunction structure in which the base magnetic pole part 11 and theembedded magnetic pole part 20 are joined together. As shown in FIGS. 1and 6, a joint surface 14 between the base magnetic pole part 11 andembedded magnetic pole part 20 (the joint surface between the innerperiphery of the base depression 11 d in the base magnetic pole part 11and a side face part of the embedded magnetic pole part 20, a part closeto the ABS 30 in particular) blocks the emission of remnantmagnetization mr from the embedded magnetic pole part 20 to the basemagnetic pole part 11. As a consequence, the thin-film magnetic headstructures 300, 301 can make a thin-film magnetic head with reducedremnant magnetization mr directed to the ABS 30 (see FIG. 8). Therefore,using the thin-film magnetic head structures 300, 301 can manufacture athin-film magnetic head which can effectively prevent the pole erasurefrom occurring.

Meanwhile, in the case of a conventional PMR in general, the mainmagnetic pole layer is preferably a magnetic material having a smallmaximum coercivity Hc (on the order of 2 to 10 Oe) and a smallmagnetostriction λ (1 to 3×10⁻⁶), while it is also preferably a magneticmaterial having a small magnetostriction λ in order to eliminate thepole erasure.

In order to avoid impairment in the overwrite characteristic whichoccurs with flux saturation even if the track width is narrowed toimprove the recording density, the magnetic material of the mainmagnetic pole layer is preferably formed of a magnetic material with ahigh saturated magnetic flux density. However, this makes it harder toreduce the magnetostriction λ of the main magnetic pole layer. In viewof this point, the above-mentioned thin-film magnetic head structures300, 301 form the main magnetic pole layer 10 as an embedded junctionstructure made of the base magnetic pole part 11 and embedded magneticpole part 20 having respective saturated magnetic flux densitiesdifferent from each other, while the saturated magnetic flux density ofthe yoke magnetic pole part 20 is made lower than that of the basemagnetic pole part 11, so as to reduce the magnetostriction λ of theembedded magnetic pole part 20. This makes the main magnetic pole layer10 reduce the magnetostriction λ as a whole. Hence, using the thin-filmmagnetic head structures 300, 301 yields a thin-film magnetic head 300A,301A which can more effectively prevent the pole erasure from occurring.

In the thin-film magnetic head structures 300, 301, the upper yokemagnetic pole part 45 is joined to the base magnetic pole part 11 andembedded magnetic pole part 20 in order to enhance the quantity ofmagnetism. Therefore, both the thin-film magnetic head structures 300,301 can enhance the quantity of magnetism of the main magnetic polelayer 10 in the vicinity of the ABS 30. Hence, by using the thin-filmmagnetic head structures 300, 301 thin-film magnetic heads 300A, 301Ahaving a favorable overwrite characteristic can be manufactured.

Here, the thin-film magnetic head structures 300, 301 have a commonstructure in that they include the upper yoke magnetic pole part 45, andthus exhibit common operations and effects. When the whole rear face ofthe upper yoke magnetic pole part 45 is joined to the embedded magneticpole part 20 as in the thin-film magnetic head structure 300, however,it becomes harder to reduce the magnetostriction λ as the main magneticlayer 10 as a whole increases the quantity of magnetism because of theupper yoke magnetic pole 45 joined thereto, whereby the pole erasure isless likely to be prevented from occurring. Therefore, in the thin-filmmagnetic head structure 301, the intervening insulative film 22 isprovided, so that the upper yoke magnetic pole part 45 is joined to thebase magnetic pole part 10 and embedded magnetic pole part 20 at thefirst contact area 45 a and the second contact area 45 b necessary forjoining with the write shield layer 40. Thus, in the thin-film magnetichead structure 301 in particular, the intervening insulative film 22blocks the emission of remnant magnetization from the upper yokemagnetic pole part 45 to the embedded magnetic pole part 20, so as toprevent the pole erasure from occurring, and enhances the quantity ofmagnetization due to the upper magnetic pole part 45, thereby making theoverwrite characteristic favorable.

On the other hand, the thin-film magnetic head structures 300, 301include the insulating layer 1 provided with the cavity 2, in which themain magnetic pole layer 10 is embedded, whereby the followingoperations and effects are exhibited. The operations and effects of thethin-film magnetic head structures 300, 301 and thin-film magnetic headsmanufactured by using the thin-film magnetic head structures 300, 301will now be explained in comparison with the conventional PMRs.

In order for the ABS-side portion of the magnetic pole end part in themain magnetic pole layer to be formed like a bevel, the followingprocedure has been employed in conventional PMRs. Namely, in theconventional PMRs, there has been a case where, as shown in FIG. 25(A),a main magnetic pole layer 501 formed on an insulating layer 500 isformed with an insulating layer 502 made of alumina, and is subjected toion beam etching (hereinafter referred to as “IBE”) by directirradiation with ion beams P. In this case, the etching speed by the IBEis slower in the magnetic pole end part in the main magnetic pole layer501 than in the insulating layer 500, whereby the IBE must be performedfor a long time in order for the magnetic pole end part to attain abevel form. As a consequence, the ABS-side portion of the magnetic poleend part tends to have a form including a narrowed part 501 a with asmaller diameter as shown in FIG. 25(B).

Therefore, even when the main magnetic pole layer 501 is intended to beformed as shown in FIG. 26(A), a narrow band part 501 b corresponding tothe track width may retract as shown in FIG. 26(B), so as to yield aflare point, thereby making the neck height NH longer than its expectedlength (about 0.15 μm) by d (about 0.2 to 0.3 μm). Therefore, theconventional PMRs have been hard to increase the quantity ofmagnetization in places near the ABS 503, which makes it difficult toyield a favorable overwrite characteristic (a characteristic by whichdata recorded on a recording medium is overwritten with other kinds ofdata).

The magnetic pole end part in the main magnetic pole layer 501 hasconventionally been formed by plating using photolithography. In orderfor the ABS-side portion to have a bevel form, a resist pattern 504having a taper angle as shown in FIG. 27(A) may be used. When the trackwidth is to be narrowed in order to improve the recording density inthis case, the ion beams P must be emitted after removing the resistpattern 504 as shown in FIG. 27(B), so as to perform trimming with theIBE for a long time. This may make the track width unfavorable ordeteriorate the yield.

On the other hand, it has been quite difficult to perform plating whileusing a narrow resist pattern, thus leaving a fear of the formedmagnetic pole end part falling down because of the IBE as shown in FIGS.28(A) and (B).

Thus, the conventional PMRs have also been problematic in that the mainmagnetic pole layer becomes harder to form reliably when the recordingdensity is to be improved.

By contrast, the thin-film magnetic head structures 300, 301 include theinsulating layer 1 provided with the cavity 2, in which the mainmagnetic pole layer 10 is embedded, and thus can eliminate all of theforegoing problems.

Namely, since the cavity 2 is sunken into a form corresponding to theouter shape of the main magnetic pole layer 10, the main magnetic polelayer 10 can be formed in the shape and dimensions as set when formed soas to be embedded into the cavity 2. Since the track width is determinedby the very narrow groove part 3 of the cavity 2, there is no need toperform the IBE for a long time at all in order for the magnetic poleend part to have a bevel form. Therefore, the neck height can be set toa value as assumed, the quantity of magnetism in places near the ABS 403can be enhanced, and a thin-film magnetic head having a favorableoverwrite characteristic can be manufactured.

The track width can be narrowed if the width of the narrow groove part 3is reduced as much as possible, whereas the narrow groove part 3 can setthe track width to a value assumed. Therefore, not only the track widthis narrow, but also the dimensional accuracy and yield become favorable,and there is no fear of the formed magnetic pole end part falling down.Therefore, providing the cavity 2 as in the thin-film magnetic headstructures 300, 301 can reliably form the main magnetic pole layerhaving an enhanced recording density.

Modified Example 1

In the above-mentioned thin-film magnetic head structure 301, as shownin FIG. 6(B), two layers composed of the alumina (Al₂O₃) film 16 a andnomagnetic film 16 b exist on the surface of the insulating film 1 onthe side closer to the thin-film coil 100, whereas the recording gaplayer 24 is formed on these layers. However, as shown in FIG. 9, athin-film magnetic head structure 302 may be constructed such that a Tafilm 16 d is formed on the surface of the insulating layer 1 whereas therecording gap layer 24 is formed on the Ta film 16 d. In this case, thethin-film magnetic head structure 302 also exhibits operations andeffects similar to those of the thin-film magnetic head structures 300,301 and the thin-film magnetic heads 300A, 301A manufactured by usingthe thin-film magnetic head structures 300, 301.

Modified Example 2

As in the thin-film magnetic head structure 303 shown in FIG. 10, aninsulating film 16 e may be provided so as to surround the Ta film 16 din the above-mentioned thin-film magnetic head structure 302, with therecording gap layer 24 being formed on the Ta film 16 d and insulatingfilm 16 e. Operations and effects similar to those of theabove-mentioned thin-film magnetic head structures 300, 301 and thethin-film magnetic heads 300A, 301A manufactured by using the thin-filmmagnetic head structures 300, 301 are also exhibited in this case.

Method of Manufacturing Thin-Film Magnetic Head Structure

With reference to FIGS. 1, 3(A) and (B), 4(B) and 6(A) and (B) mentionedabove and FIGS. 11(A), (B), (C), and (D) to 16(A) and (B), a method ofmanufacturing the thin-film magnetic head structure 301 in accordancewith the first embodiment having the above-mentioned structure will nowbe explained.

FIGS. 11 to 14 show plan or sectional views in respective steps of themanufacturing method, in which (A) is a plan view, (B) is a sectionalview taken along the line B-B of (A), (C) is a plan view showing a majorpart of (A) under magnification, and (D) is a sectional view taken atthe ABS 30 of (B). For convenience of illustration, (C) in each drawingshows the major part of (A) under magnification with changed ratios ofdimensions. In FIG. 15, (A) is a plan view focused on the interveninginsulative film in the middle of manufacture, (B) is a sectional viewtaken along the line B-B of (A), and (C) is a sectional view taken atthe ABS 30 in (B). In FIG. 16, (A) is a sectional view corresponding tothe line B-B in FIG. 15(A), whereas (B) is a sectional view taken at theABS 30 in (A).

First, in the manufacturing method in accordance with this embodiment, areproducing head structure comprising an MR device (magnetoresistivedevice) and the like is laminated on an undepicted substrate made ofaluminum oxide titanium carbide (Al₂O₃·TiC), for example. Subsequently,an insulating layer 1 is formed from alumina (Al₂O₃) or a nonmagneticmaterial.

After a photoresist is applied onto the insulating layer 1, patterningis performed with a predetermined photomask, so as to yield a resistpattern exposing the surface of the insulating layer 1 into a formcorresponding to the cavity 2. Using this resist pattern as a mask,reactive ion etching (hereinafter referred to as “RIE”) is carried out,so as to remove the part of insulating layer 1 not covered with theresist pattern, whereby the cavity 2 is formed as shown in FIGS. 3(A)and (B). The (very narrow groove part 3 of the) cavity 2 formed at thattime determines the track width and neck height NH of the thin-filmmagnetic head.

Next, as shown in FIGS. 11(A), (B), (C), and (D), a CVD-Al₂O₃ film(alumina film) 16 a is formed on the whole surface of the insulatinglayer 1 by a thickness of 100 to 500 Å by the atomic layer method inorder to adjust the track width. Instead of the alumina film 16 a, acoating made of Ta, W, TiN, or the like may be formed by a thickness ofabout 200 to 500 Å by CVD or sputtering. Subsequently, a nonmagneticfilm 16 b is formed by a thickness of about 400 to 600 Å by sputteringor IBD (ion beam deposition) so as to cover the cavity 2. It will bepreferred if the nonmagnetic film 16 b is formed from a Ta film or an Rufilm whose resistance is lower than that of the Ta film, since thusformed film becomes a seed electrode for plating a magnetic materialwhich will be explained later. In this case, the resistance ispreferably lower. Thereafter, a magnetic film 16 c made of CoFeN (24 kG)or CoNiFe (10 kG) is formed on the whole surface of the insulating layer1 by a thickness of 300 to 600 Å. The magnetic film 16 c can be omittedas appropriate when the nonmagnetic film 16 b made of the Ta film or Rufilm to become the seed electrode is formed.

Subsequently, using a first magnetic material made of CoNiFe or CoFehaving a high saturated magnetic flux density (about 2.3 to 2.4 T), aplating film 27 for forming the film-like magnetic pole part of thepresent invention is formed on the magnetic film 16 c as shown in FIGS.12(A), (B), (C), and (D). This plating film 27 can selectively be formedon the whole surface of the insulating layer 1 or only within the cavity2. The plating film 27 is embedded in the very narrow groove part 3 ofthe cavity 2. However, the area other than the very narrow groove part 3in the cavity 2, i.e., the area of the variable width depression 4 andfixed width depression 5, is wider than the very narrow groove part 3and thus is not filled with the plating film 27, whereby a film-likemagnetic pole part 27 a is formed on the inner periphery of the cavity 2in the area other than the very narrow groove part 3. The film-likemagnetic pole part 27 a is continuously formed until the very narrowgroove part 3 is filled (with the plating film 27), whereby thefilm-like magnetic pole part 27 a is formed like a thin film having athickness corresponding to the size (volume) of the very narrow groovepart 3. Here, the very narrow groove part 3 is a very narrow area.Therefore, the film-like magnetic pole part 27 a attains a very smallfilm thickness of 0.1 to 0.2 μm when formed until the very narrow groovepart 3 is filled. When the film-like magnetic pole part 27 a is verythin, an embedded magnetic pole part 20 to be explained later is locatedvery close to the base magnetic pole part 11, by which the neck heightNH can be made longer while suppressing the occurrence of pole erasure,whereby the track width becomes stable when cut at the ABS 30.

Next, as shown in FIGS. 13(A), (B), (C), and (D), a plating film 28 forembedding a second magnetic material different from the first magneticmaterial into the inside of the film-like magnetic pole part 27 a isformed. Here, a magnetic material (e.g., a soft material such as FeNihaving a saturated magnetic flux density of about 2.1 T or CoNiFe havinga saturated magnetic flux density of about 1.9 T) whose saturatedmagnetic flux density is lower than that of the first magnetic materialis used as the second magnetic material. Embedding the second magneticmaterial yields an embedded junction structure in which the film-likemagnetic pole part 27 a using the first magnetic material and theplating film 28 using the second magnetic material are joined together,and simultaneously forms a joint surface 14 between the film-likemagnetic pole part 27 a and the plating film 28. In the plating film 28,the second magnetic material embedded in the inside of the film-likemagnetic pole part 27 a becomes the embedded magnetic pole part 20 aswill be explained later.

Subsequently, as shown in FIGS. 14(A), (B), (C), and (D), the wholesurface of the substrate including the surface of the plating films 27and 28 on the side closer to the thin-film coil 100 is subjected tochemical mechanical polishing (hereinafter referred to as “CMP”) as asurface-flattening process. As a result of the surface-flatteningprocess, the first magnetic material embedded in the very narrow groovepart 3 forms a magnetic pole end part 11 a, thus yielding a mainmagnetic pole layer 10 having an embedded junction structure in which abase magnetic pole part 11 composed of the magnetic pole end part 11 aand film-like magnetic pole part 27 and the embedded magnetic pole part20 constituted by the second magnetic material are joined together.Here, the nonmagnetic film 16 b made of Ta, Ru, or the like functions asa stopper, so that the height h1 from the bottom face of the insulatinglayer 1 to the surface of the base magnetic pole part 11 and embeddedmagnetic pole part 20 is regulated such that the depth d1 of the cavity2 (see FIG. 4(B)) is on the order of 0.2 to 0.35 μm.

Next, as shown in FIGS. 15(A), (B), and (C), a coating 34 for forming arecording gap layer 24 and an intervening insulative film 22 is formedby a thickness of 400 to 500 Å so as to cover the whole upper face ofthe substrate including the base magnetic pole part 11 and embeddedmagnetic pole part 20. The material of the coating 34 may be either aninsulating material such as alumina or a nonmagnetic metal material suchas Ru, NiCu, Ta, W, Cr, Al₂O₃, Si₂O₃, or NiPd.

Thereafter, in the coating 34, a part to be formed with a first shieldpart 41, and a first contact area 45 a and a second contact area 45 bwhich are used for joining an upper yoke magnetic pole part 45 to beexplained later to the base magnetic pole part 11 and embedded magneticpole part 20 are opened, and then the first shield part 41 and the yokemagnetic pole part 45 are formed. In this case, the first shield part 41is formed so as to oppose the magnetic pole end part 11 a of the basemagnetic pole part 11 by way of the recording gap layer 24 in order todefine the neck height NH. The upper yoke magnetic pole part 45 isconnected to portions where the intervening insulative film 22 does notexist, i.e., at the first and second contact areas 45 a, 45 b. In thiscase, the intervening insulative film 22 is formed by the part ofcoating 34 disposed between the embedded magnetic pole part 20 and theupper yoke magnetic pole part 45 at a position distanced farther fromthe ABS 30 than the recording gap layer 24. The foregoing first shieldpart 41 and upper yoke magnetic pole part 45 can be formed by platingwith a magnetic material of CoNiFe (1.9 to 2.4 T) or NiFe (0.8 to 1.2 T)so as to attain a thickness of 0.8 to 1.2 μm.

For improving the overwrite characteristic by enhancing the quantity ofmagnetization in the main magnetic pole layer 10 as a whole, it will bepreferred that the upper yoke magnetic pole part 45 is formed by amagnetic material having a higher saturated magnetic flux density. Onthe other hand, the pole erasure is more likely to occur as thesaturated magnetic flux density of the upper yoke magnetic pole part 45is higher. When the intervening insulative film 22 is formed, and theupper yoke magnetic pole part 45 is joined to the embedded magnetic polepart 20 by way of the first and second contact areas 45 a, 45 b on thesides of the embedded magnetic pole part 20 closer to and farther fromthe ABS 30 as mentioned above, however, the occurrence of pole erasurecan be suppressed even when the saturated magnetic flux density of theupper yoke magnetic pole part 45 is made higher.

Next, a coating made of alumina (Al₂O₃) having a thickness of 0.5 to 1.2μm, for example, is formed so as to cover the whole upper face of thesubstrate, whereby an insulating part 51 is formed so as to enter thegap between the first shield part 41 and the upper yoke magnetic polepart 45 (see FIGS. 16(A) and (B)). Then, the surface of the first shieldpart 41 and yoke magnetic pole part 45 is subjected to CMP as aflattening process so as to yield a thickness on the order of 0.3 to 0.6μm. Thereafter, a coating made of alumina (Al₂O₃) having a thickness of0.2 to 0.3 μm, for example, is formed, and a portion to be formed with asecond shield part 42 is selectively opened, whereby an insulating layer31 is formed.

Subsequently, as shown in FIGS. 16(A) and (B), an electrode film (notdepicted) made of a conductive material and a frame produced byphotolithography are formed on the insulating layer 31 as shown in FIGS.16(A) and (B), and electroplating using the electrode film is carriedout, so as to form a plating layer made of Cu. This plating layer andthe electrode film thereunder become the thin-film coil 100. Thethin-film coil 100 is formed on the yoke magnetic pole part 45 by way ofthe insulating layer 31.

Next, though not depicted, a frame is formed by photolithography, andthe second shield part 42 is formed by frame plating. The same magneticmaterial as that of the first shield part 41 is used for the secondshield part 42. The thin-film coil 100 and second shield part 42 areformed by a thickness of 2.5 to 3.5 μm. A photoresist 101 is applied soas to cover the whole upper face of the substrate, and is embedded ininterstices of the thin-film coil 100.

Thereafter, an alumina (Al₂O₃) film is formed by a thickness on theorder of 3.0 to 4.0 μm on the thin-film coil 100, and then the wholesurface is subjected to CMP as a surface-flattening process (see FIG.16). Subsequently, an insulating layer made of alumina (Al₂O₃) is formedby a thickness of about 0.2 μm so as to cover the whole upper face ofthe substrate, and then an opening is provided at the portion formedwith the second shield part 42. This yields an insulating layer 32 forinsulating the thin-film coil 100 and a third shield part 43 from eachother so that no short-circuiting occurs therebetween. Next, the thirdshield part 43 is formed by a thickness on the order of 2 to 2.5 μm,whereby a write shield layer 40 is formed. Thereafter, an overcoat layer37 made of alumina is formed so as to cover the third shield part 43.

The foregoing steps yield the thin-film magnetic head structure 301shown in FIGS. 6(A) and (B) and 7. Thus obtained thin-film magnetic headstructure 301 has the above-mentioned configuration, and thus caneffectively prevent the pole erasure from occurring, while improving therecording density. Cutting the thin-film magnetic head structure 301 atthe ABS 30 yields the thin-film magnetic head 301A in accordance withthe present invention. The thin-film magnetic head 301A exhibitsoperations and effects similar to those of the thin-film magnetic headstructure 301.

Second Embodiment

Configuration of Thin-Film Magnetic Head Structure

The thin-film magnetic head structure in accordance with a secondembodiment of the present invention will now be explained with referenceto FIGS. 17(A) and (B), 18(A), (B), and (C), and 19(A) and (B). FIG. 17is a sectional view of the thin-film magnetic head structure 310 inaccordance with the second embodiment of the present invention, in which(A) is a sectional view taken along a direction intersecting thethin-film coil, and (B) is a sectional view showing the ABS when cut atthe ABS. FIG. 18 is a view showing a base insulating layer, in which (A)is a plan view, (B) is a sectional view taken along the line B-B in (A),and (C) is a sectional view taken along the line C-C in (A). FIG. 19 isa view showing the main magnetic pole layer 10A′ after being cut alongthe ABS, in which (A) is a perspective view, and (B) is a sectional viewtaken along the line B-B of (A). In FIGS. 17, 18, and 19 (as with FIGS.20 to 24) used for explaining the thin-film magnetic head structure 310,members and parts similar to those in the thin-film magnetic headstructure 300 will be referred to with numerals identical thereto,without repeating their overlapping descriptions.

Configuration of Thin-Film Magnetic Head Structure

An insulating layer 7 is made of alumina (Al₂O₃) and has a cavity 70 ata center part on the surface side to be formed with a recording head.The cavity 70 is a magnetic pole forming depression in the presentinvention, and is sunken into a form corresponding to the outer shape ofa main magnetic pole layer 10A′ in order to form the main magnetic polelayer 10A′ with set dimensions and form. The cavity 70, which will beexplained in detail in a manufacturing method to be mentioned later, isformed prior to the main magnetic pole layer 10A′ as shown in FIG. 17.The cavity 70 includes a very narrow groove part 3 and a protrudeddepression 6, and further includes a variable width depression 74 andfixed width depressions 75, 76. In the variable width depression 74, thepart connecting with the very narrow groove part 3 includes a first area74 a having a first depth dp1 equal to that of the very narrow groovepart 3 and a second area 74 b, connected to the first area 74 a, havinga depth dp2 greater than the dp1. In the cavity 70, a stepped line Lwhich is a boundary between the first area 74 a and second area 74 b, isdisposed at a position distanced farther from the ABS 30 than therecording gap layer 24, thus yielding a variable depth structure whosedepth changes at the stepped line L. The fixed width depression 75 hasthe depth of dp2. At a position distanced farther from the ABS 30 thanthe first area 74 a, the fixed depression 76 has a fixed width broaderthan that of the fixed depression 75. The fixed width depression 76 hasa depth of dp3 corresponding to the difference between the depths dp2and dp1.

As shown in FIG. 19, the main magnetic pole layer 10A′ (as with the mainmagnetic pole layer 10A before cutting) includes a base magnetic polepart 11A′ and an embedded magnetic pole part 20A′, and is joined to anupper yoke magnetic pole part 45′. FIG. 19 is a view showing the mainmagnetic pole layer 10A′ after being cut along the ABS 30, in which (A)is a perspective view, and (B) is a sectional view taken along the lineB-B of (A). For convenience of illustration, FIG. 19 shows the upperyoke magnetic pole part 45′ by dash-double-dot lines. The main magneticpole layer 10′ is formed so as to be embedded in the cavity 70. Theembedded magnetic pole part 20A′ is made of a magnetic material having asaturated magnetic flux density lower than that of the base magneticpole part 11′, whereas the upper yoke magnetic pole part 45′ is made ofa magnetic material having a saturated magnetic flux density higher thanthat of the embedded magnetic pole part 20A′.

The base magnetic pole part 11′ (as with the base magnetic pole part 11before cutting) includes a magnetic pole end part 11 a having a verynarrow width corresponding to the very narrow groove part 3, and a yokepart 11 f corresponding to the variable width depression 74 and fixedwidth depressions 75, 76. Since the variable width depression 74includes the first area 74 a (with the depth dp1) and second area 74 b(with the depth dp2) having thicknesses different from each other asmentioned above, the yoke part 11 f corresponding to the variable widthdepression 74 includes a first area 11 g (with the depth dp1) and asecond area 11 h (with the depth dp2) having thicknesses different fromeach other. The yoke part 11 f has a stepped part 23, disposed at aposition distanced farther from the ABS 30 than the recording gap layer24, as a junction between the first area 11 g and second area 11 h, andchanges the thickness at the stepped part 23 (such that the second area11 h is thicker than the first area 11 g). The yoke part 11 f is formedwith an expanded area 11 j having a width expanded along the ABS 30 soas to correspond to the fixed width depression 76.

Leaving a peripheral area 11 k corresponding to the variable widthdepression 74 and fixed depressions 75, 76, the inside of the yoke part11 f is a base depression 11 m, in which the embedded magnetic pole part20A′ is buried. The yoke part 11 f is joined to all the side and bottomfaces of the embedded magnetic pole part 20 excluding the upper face. Asa consequence, the main magnetic pole layer 10A′ has an embeddedjunction structure in which the yoke part 11 f excluding the magneticpole end part 11 a of the base magnetic pole part 11A′ and the embeddedmagnetic pole part 20A′ buried in the base depression 11 m are joinedtogether. Here, a magnetic material (soft material) having a saturatedmagnetic flux density lower than that of the magnetic material (Hi-Bsmaterial) used in the base magnetic pole part 11A′ is employed as amagnetic material constructing the embedded magnetic pole part 20A.

Other configurations and the like are in common with the thin-filmmagnetic head structure 300, and thus will not be explained.

When the thin-film magnetic head structure 310 having the foregoingconfiguration is cut at an intermediate part of the very narrow groovepart 3 so as to form the ABS 30, a thin-film magnetic head 310A (seeFIG. 17) is obtained.

As with the thin-film magnetic head structures 300 to 303, the thin-filmmagnetic head structure 310 employs a magnetic material (Hi-Bs material)having a higher saturated magnetic flux density for the base magneticpole layer 11A in the main magnetic pole layer 10A, so as to prevent theoverwrite characteristic from deteriorating, and uses a magneticmaterial (soft material) having a lower saturated magnetic flux densityfor the embedded magnetic pole part 20A, so as to lower themagnetostriction λ, thereby eliminating the pole erasure.

On the other hand, the yoke part 11 f includes a second area 11 h havinga larger thickness on the side distanced from the ABS 30 by way of thestepped part 23 in the thin-film magnetic head 310 unlike the thin-filmmagnetic heads 300 to 303. As the yoke part 11 f includes the secondarea 11 h, the main magnetic pole layer 10 can enhance the quantity ofmagnetism by the increase in thickness from the first area 11 g. As thequantity of magnetism is enhanced by the second area 11 h, the overwritecharacteristic is further improved.

In the thin-film magnetic head structure 310, the yoke part 11 f isprovided with the expanded area 11 j whose width broadens along the ABS30. The main magnetic pole layer 10 having the expanded area 11 j canfurther enhance the quantity of magnetism in the vicinity of the ABS 30,whereby the overwrite characteristic of the thin-film magnetic headstructure 310 further improves.

Method of Manufacturing Thin-Film Magnetic Head Structure

The method of manufacturing the thin-film magnetic head structure 310differs from the method of manufacturing the thin-film magnetic headstructure 300 in the steps carried out until the base magnetic pole part11A′ and embedded magnetic pole part 20A′ are formed and in that itlacks the step of forming the intervening insulative film 22, whereastheir subsequent steps are substantially in common. Therefore, the stepscarried out until the base magnetic pole part 11A′ and embedded magneticpole part 20A′ are formed will mainly be explained, whereas similarsteps in the subsequent steps will be omitted or simplified.

FIGS. 20 to 24 show plan or sectional views in respective steps of themanufacturing method, in which FIGS. 20(A) to 22(A) and 24(A) are planviews, whereas (B) is a sectional view taken along the line B-B of (A).(C) is a plan view showing a major part of (A) under magnification,whereas (D) is a sectional view taken at the ABS 30 of (B). Forconvenience of illustration, (C) in each drawing shows the major part of(A) under magnification with changed ratios of dimensions. In FIG. 23,(A) is a sectional view corresponding to the line B-B in FIG. 22(A),whereas (B) is a sectional view taken at the ABS 30 of (A).

The steps carried out until the insulating layer 7 is formed are incommon with the steps of forming the insulating layer 7 in the thin-filmmagnetic head structure 301, and thus will not be explained.

After the insulating layer 7 is formed, a photoresist is applied ontothe insulating layer 7 as shown in FIGS. 20(A), (B), (C), and (D), andpatterning using a predetermined photomask is performed, so as to form aresist pattern exposing the surface of the insulating layer 7 into aform corresponding to a first cavity 70 a. The first cavity 70 a has aform in common with the above-mentioned cavity 2. Then, using the resistpattern as a mask, RIE is performed, so as to eliminate the part ofinsulating layer 7 not covered with the resist pattern, thereby formingthe first cavity 70 a such that the depth dp1 (see FIG. 18) is on theorder of 0.2 to 0.4 μm. The very narrow groove part 3 of the firstcavity 70 a defines the track width (0.09 to 0.12 μm) and neck height NHof the thin-film magnetic head.

Thereafter, the photoresist is further applied onto the insulating layer7, and patterning with a predetermined photomask is carried out, so asto form a resist pattern RP which exposes the surface of the insulatinglayer 7 into a form corresponding to the second cavity 70 b. The secondcavity 70 b is a substantially rectangular area having one sideextending along the ABS 30. This side corresponds to the above-mentionedstepped line L. For forming the second cavity 70 b on the side distancedfrom the ABS 30 by way of the stepped line L, the resist pattern RPcovers the very narrow groove part 3, the protruded depression 6, andthe variable width depression (first area 74 a) on the side closer tothe ABS 30 in the first cavity 70 a, while opening a substantiallyrectangular area whose width is greater than that of the first cavity 70a.

Using the resist pattern RP as a mask, RIE is performed, so as toeliminate the part of insulating layer 7 not covered with the resistpattern RP. This forms the second cavity 70 b, whereas the forming ofthe second cavity 70 b and the above-mentioned first cavity 70 a yieldsa cavity 70 corresponding to the magnetic pole forming depression in thepresent invention. Here, the overlapping area (hatched part in FIG.20(A)) between the first cavity 70 a and second cavity 70 b, which isconstituted by the variable width depression (second area 74 b) andfixed width depression 75 on the side of the stepped line L distancedfarther from the ABS 30 than a recording gap layer 24 to be formedlater, has been subjected to RIE twice. Consequently, a step where thedepth changes occurs in the peripheral part of the overlapping area.This yields a variable depth structure in which the depth dp2 of theoverlapping area is greater than the depth dp1 on the ABS 30 side asshown in FIGS. 18(A), (B), and (C).

Forming the second cavity 70 b yields an expanded area 70 f whose widthextends along the ABS 30. The depth dp3 of the expanded area 70 f is avalue obtained when subtracting the depth dp1 of the first cavity 70 afrom the depth dp2 of the overlapping area.

Thereafter, the resist pattern RP is eliminated as shown in FIGS. 21(A),(B), (C), and (D), then an alumina film 16 a is formed in order toadjust the track width as shown in FIGS. 22(A), (B), (C), and (D), andsubsequently a nonmagnetic film 16 b and a magnetic film 16 c are formedon the whole surface of the insulating layer 7. The forming of aluminafilm 16 a, nonmagnetic film 16 b, and magnetic film 16 c is in commonwith the method of manufacturing the thin-film magnetic head structure301, and thus will not be explained.

Next, using CoNiFe or CoFe which is a first magnetic material having ahigh saturated magnetic flux density (on the order of 2.3 to 2.4 T), aplating film 71 is formed on the magnetic film 16 c as shown in FIGS.23(A) and (B). As in the method of manufacturing the thin-film magnetichead structure 301, the plating film 71 is continuously formed until thevery narrow groove part 3 is filled with the plating film 71, whereby afilm-like magnetic pole part 71 a is formed on the inner periphery ofthe cavity 70 except for the very narrow groove part 3. Thus formedfilm-like magnetic pole part 71 a has a very thin film thickness of 0.1to 0.2 μm. Since the film-like magnetic pole part 71 a is very thin, anembedded magnetic pole part 20A to be formed later is located very closeto the base magnetic pole part 11A.

Thereafter, as in the method of manufacturing the thin-film magnetichead structure 301, a plating film 72 for embedding a second magneticmaterial different from the first magnetic material into the inside ofthe film-like magnetic pole part 71 a is formed. Here, a magneticmaterial (e.g., a soft material such as FeNi having a saturated magneticflux density of about 2.1 T or CoNiFe having a saturated magnetic fluxdensity of about 1.9 T) whose saturated magnetic flux density is lowerthan that of the first magnetic material is used as the second magneticmaterial. Embedding the second magnetic material yields an embeddedjunction structure in which the film-like magnetic pole part 71 a usingthe first magnetic material and the plating film 72 using the secondmagnetic material are joined together, and forms a joint surface 14A.

Subsequently, as shown in FIGS. 24(A), (B), (C), and (D), the wholesurface of the substrate including the surface of the plating film 71and the plating film 72 on the side closer to the thin-film coil 100 issubjected to chemical mechanical polishing (hereinafter referred to as“CMP”) as a surface-flattening process as in the method of manufacturingthe thin-film magnetic head structure 301. As a result of thesurface-flattening process, the first magnetic material embedded in thevery narrow groove part 3 forms a magnetic pole end part 11 a, thusyielding a main magnetic pole layer 10A having an embedded junctionstructure in which a base magnetic pole part 11A composed of themagnetic pole end part 11 a and film-like magnetic pole part 71 a andthe embedded magnetic pole part 20A constituted by the second magneticmaterial are joined together.

In the cavity 70 in which the plating film 71 and the plating film 72are embedded, the depth dp2 (see FIG. 18) in the overlapping areabetween the first cavity 70 a and second cavity 70 b is deeper, so thatthe thickness of the base magnetic pole part 11A and embedded magneticpole part 20A corresponding to the overlapping area is greater than thethickness in the other area (the thickness of the magnetic pole end part11 a in particular). Therefore, the quantity of magnetization in thebase magnetic pole part 11A and embedded magnetic pole part 20Aincreases as the thickness is greater.

The second cavity 70 b is formed with the expanded area 70 f, wherebythe width of the base magnetic pole part 11A and embedded magnetic polepart 20A in their portion corresponding to the expanded area 70 f isbroader along the ABS 30.

Thereafter, for forming a recording gap layer 24 (see FIG. 17), acoating made of an insulating material such as alumina or a nonmagneticmetal material such as Ru, NiCu, Ta, W, Cr, Al₂O₃, Si₂O₃, or NiPd isformed by 400 to 500 Å. Though this method does not include a step offorming the intervening insulative film 22 such as the one explained inthe method of manufacturing the thin-film magnetic head structure 301,the step of forming the intervening insulative film 22 may be providedas in the method of manufacturing the thin-film magnetic head structure301.

Then, a first shield part 41 (see FIG. 17) is formed so as to oppose themagnetic pole end part 11 a by way of the recording gap layer 24 inorder to define the neck height NH. An upper yoke magnetic pole part 45is formed so as to join with the base magnetic pole part 11 and embeddedmagnetic pole part 20 at a portion not covered with the recording gaplayer 24.

Subsequent steps are in common with the above-mentioned method ofmanufacturing the thin-film magnetic head structure 301, and thus willnot be explained.

The foregoing steps yield the thin-film magnetic head structure 310shown in FIGS. 17(A) and (B). Thus obtained thin-film magnetic headstructure 310 has the above-mentioned configuration, and thus caneffectively prevent the pole erasure from occurring, while improving therecording density. Cutting the thin-film magnetic head structure 310 atthe ABS 30 yields the thin-film magnetic head 310A in accordance withthe present invention. The thin-film magnetic head 310A also exhibitsoperations and effects similar to those of the thin-film magnetic headstructure 310.

It is apparent that various embodiments and modifications of the presentinvention can be embodied, based on the above description. Accordingly,it is possible to carry out the present invention in the other modesthan the above best mode, within the following scope of claims and thescope of equivalents.

1. A thin-film magnetic head structure adapted to manufacture athin-film magnetic head configured such that a main magnetic pole layerincluding a magnetic pole end part on a side of a medium-opposingsurface opposing a recording medium, a write shield layer opposing themagnetic pole end part so as to form a recording gap layer on themedium-opposing surface side, and a thin-film coil wound about the writeshield layer or main magnetic pole layer are laminated; wherein the mainmagnetic pole layer includes a base magnetic pole part comprising themagnetic pole end part and a base depression distanced farther from themedium-opposing surface than the magnetic pole end part, and an embeddedmagnetic pole part buried in the base depression and joined to the basemagnetic pole part; and wherein the thin-film magnetic head structureincludes: a yoke magnetic pole part joined to the base magnetic polepart and embedded magnetic pole part at a position distanced fartherfrom the medium-opposing surface than the recording gap layer, and anintervening insulative film disposed between the embedded magnetic polepart and yoke magnetic pole part at a position distanced farther fromthe medium-opposing surface than the recording gap layer.
 2. A thin-filmmagnetic head structure according to claim 1, further comprising a baseinsulating layer including a magnetic pole forming depression sunkeninto a form corresponding to the main magnetic pole layer, the magneticpole forming depression having a very narrow groove part formed so as todefine a track width of the thin-film magnetic head; wherein the basemagnetic pole part is arranged at the magnetic pole forming depressionin the base insulating layer.
 3. A thin-film magnetic head structureaccording to claim 2, wherein the base magnetic pole part and theembedded magnetic pole part are joined to each other at a first contactarea disposed between the medium-opposing surface and the thin-filmcoil, and at a second contact area disposed at a position distancedfarther from the medium-opposing surface than the thin-film coil.
 4. Athin-film magnetic head structure according to claim 2, wherein the basemagnetic pole part has a saturated magnetic flux density set higher thanthat of the embedded magnetic pole part.
 5. A thin-film magnetic headstructure according to claim 1, wherein the base magnetic pole part hasa saturated magnetic flux density set higher than that of the embeddedmagnetic pole part.
 6. A thin-film magnetic head structure according toclaim 1, wherein the base magnetic pole part and the embedded magneticpole part are joined to each other at a first contact area disposedbetween the medium-opposing surface and the thin-film coil, and at asecond contact area disposed at a position distanced farther from themedium-opposing surface than the thin-film coil.
 7. A thin-film magnetichead structure adapted to manufacture a thin-film magnetic headconfigured such that a main magnetic pole layer including a magneticpole end part on a side of a medium-opposing surface opposing arecording medium, a write shield layer opposing the magnetic pole endpart so as to form a recording gap layer on the medium-opposing surfaceside, and a thin-film coil wound about the write shield layer or mainmagnetic pole layer are laminated; wherein the main magnetic pole layerincludes a base magnetic pole part comprising the magnetic pole end partand a base depression distanced farther from the medium-opposing surfacethan the magnetic pole end part, an embedded magnetic pole part buriedin the base depression and joined to the base magnetic pole part, and astepped part with a variable thickness at a position distanced fartherfrom the medium-opposing surface than the recording gap layer, thethickness at a position distanced farther from the medium-opposingsurface than the stepped part being formed greater than the thickness ata position closer to the medium-opposing surface than the stepped part;and wherein the thin-film magnetic head structure includes a yokemagnetic pole part joined to the base magnetic pole part and embeddedmagnetic pole part at a position distanced farther from themedium-opposing surface than the recording gap layer.
 8. A thin-filmmagnetic head structure according to claim 7, further comprising a baseinsulating layer including a magnetic pole forming depression sunkeninto a form corresponding to the main magnetic pole layer, the magneticpole forming depression having a very narrow groove part formed so as todefine a track width of the thin-film magnetic head; wherein the basemagnetic pole part is arranged at the magnetic pole forming depressionin the base insulating layer.
 9. A thin-film magnetic head structureaccording to claim 8, wherein the main magnetic pole layer has anexpanded area with a width expanded along the medium-opposing surface.10. A thin-film magnetic head structure according to claim 8, whereinthe magnetic pole forming depression has a variable depth structurewhose depth changes at a stepped line disposed at a position distancedfarther from the medium-opposing surface than the recording gap layer.11. A thin-film magnetic head structure according to claim 8, whereinthe base magnetic pole part has a saturated magnetic flux density sethigher than that of the embedded magnetic pole part.
 12. A thin-filmmagnetic head structure according to claim 7, wherein the main magneticpole layer has an expanded area with a width expanded along themedium-opposing surface.
 13. A thin-film magnetic head structureaccording to claim 7, wherein the magnetic pole forming depression has avariable depth structure whose depth changes at a stepped line disposedat a position distanced farther from the medium-opposing surface thanthe recording gap layer.
 14. A thin-film magnetic head structureaccording to claim 7, wherein the base magnetic pole part has asaturated magnetic flux density set higher than that of the embeddedmagnetic pole part.
 15. A thin-film magnetic head configured such that amain magnetic pole layer including a magnetic pole end part on a side ofa medium-opposing surface opposing a recording medium, a write shieldlayer opposing the magnetic pole end part so as to form a recording gaplayer on the medium-opposing surface side, and a thin-film coil woundabout the write shield layer or main magnetic pole layer are laminated;wherein the main magnetic pole layer includes a base magnetic pole partcomprising the magnetic pole end part and a base depression distancedfarther from the medium-opposing surface than the magnetic pole endpart, and an embedded magnetic pole part buried in the base depressionand joined to the base magnetic pole part; and wherein the thin-filmmagnetic head includes: a yoke magnetic pole part joined to the basemagnetic pole part and embedded magnetic pole part at a positiondistanced farther from the medium-opposing surface than the recordinggap layer, and an intervening insulative film disposed between theembedded magnetic pole part and yoke magnetic pole part at a positiondistanced farther from the medium-opposing surface than the recordinggap layer.
 16. A thin-film magnetic head configured such that a mainmagnetic pole layer including a magnetic pole end part on a side of amedium-opposing surface opposing a recording medium, a write shieldlayer opposing the magnetic pole end part so as to form a recording gaplayer on the medium-opposing surface side, and a thin-film coil woundabout the write shield layer or main magnetic pole layer are laminated;wherein the main magnetic pole layer includes a base magnetic pole partcomprising the magnetic pole end part and a base depression distancedfarther from the medium-opposing surface than the magnetic pole endpart, an embedded magnetic pole part buried in the base depression andjoined to the base magnetic pole part, and a stepped part with avariable thickness at a position distanced farther from themedium-opposing surface than the recording gap layer, the thickness at aposition distanced farther from the medium-opposing surface than thestepped part being formed greater than the thickness at a positioncloser to the medium-opposing surface than the stepped part; and whereinthe thin-film magnetic head includes a yoke magnetic pole part joined tothe base magnetic pole part and embedded magnetic pole part at aposition distanced farther from the medium-opposing surface than therecording gap layer.